University of Rochester researchers have announced the development of a new polymer, capable of supporting 1,000 times its own mass. The supple material may also be bent using the warmth from a human hand, traits that could lead to a wide variety of uses.
Polymers that can change shape when heated have been developed in the past, yet this new polymer exhibits the rare quality of becoming flexible when exposed to body heat. This property, which can be used to change the shape of a device, could make the substance useful in medical applications.
"Tuning the trigger temperature is only one part of the story. We also engineered these materials to store large amount[s] of elastic energy, enabling them to perform more mechanical work during their shape recovery," Mitch Anthamatten, a professor of chemical engineering at the University of Rochester, said.
One challenge facing researchers was learning how to control crystallization of the polymer. As similar shape-shifting materials are stretched or cooled, atomic strands of polymer molecules re-align, driving the object to stay in the "temporary" alignment. This process makes it more and more difficult to bring the object back to its "relaxed," original form.
Individual "linkers" were used to connect the molecules, reducing the effects of crystallization in the new polymer. By carefully controlling the placement of the linking chains, researchers were able to precisely direct the turning point of the material.
When the new polymer is removed from the heat source (such as a human body), the material immediately returns to its original configuration.
"Nearly all applications of shape memory polymers will require that the material pushes or pulls on its surroundings. However, researchers seldom measure the amount of mechanical work that shape-memory polymers are actually performing," Anthamatten stated in a press release.
The capability to lift 1,000 times its own mass means that a device constructed from 1/28th ounce (about the weight of a typical paper clip), could lift a one-liter bottle of water.
Applications for the new polymer could include self-fitting clothes, new generations of sutures and artificial skin. Although it is unlikely the great lifting ability of the material will ever be utilized to provide people with super-human strength, the polymer is still reminiscent of Plastic Man, a flexible superhero introduced to the world in 1941.
Development of the new super-strong material was detailed in the journal Polymer Science Part B: Polymer Physics.
